JP4253559B2 - Optical pickup device and optical disk device - Google Patents

Description

The present invention relates to an optical pickup apparatus that supports a laser light source that emits a plurality of laser beams for recording and / or reproducing information on a disk with a pickup housing, and an optical disk apparatus including the optical pickup apparatus , in particular. It relates to a cooling mechanism.

  A general optical pickup device includes a laser light source that emits light onto an optical disk, an optical component that branches or condenses light from the laser light source, and a photodetector that receives reflected light from the optical disk. Etc. When signals are detected by the optical pickup device, the fixing positions of the laser light source, the photodetector, and the optical components are important. In order to accurately perform the recording / reproducing operation, it is necessary to precisely adjust the fixed position.

  Optical discs include CDs and DVDs with different laser light source wavelengths, and it is desired that a single optical pickup device can handle both of these optical discs. For this purpose, it is necessary to increase the degree of freedom in the adjustment direction of each component in addition to the adjustment accuracy of the laser light source, the photodetector, and the optical component to the fixed positions. In addition to the laser light source, the optical pickup device includes a laser driving circuit, a high-frequency module, a photodetector, a driving coil used for the objective lens driving device, and the like as components that generate heat during recording and reproduction. Yes. As described above, since the optical pickup device has a large number of heat generating components, the optical pickup device rises due to heat generated by these heat generating components.

  In particular, in a recordable optical pickup device having a function of recording information on a disc such as a DVD-RAM / R / RW or CD-R / RW, a laser light source provided in the optical pickup device and a laser drive circuit for driving the laser light source are provided. The fever gets bigger. Further, as the recording speed increases, a high-power laser light source is required, and the laser light source and the laser drive circuit are required to be arranged close to each other. On the other hand, optical pickup devices tend to be smaller and thinner. For this reason, it tends to cause deterioration in performance of components, life deterioration, malfunction, etc. due to heat generation.

  For example, in Patent Document 1, in an optical pickup device incorporating a heat-generating laser driving circuit disposed in the vicinity of a laser light source, an optical pickup housing and a flexible laser driving circuit are disclosed. There has been disclosed an optical pickup device having a structure in which a surface facing a substrate and a surface opposite to each other are in close contact and thermally connected, and heat generated by the electronic component is released to the optical pickup casing. In this optical pickup device, the thermal resistance between the laser drive circuit and the optical pickup housing disposed in the vicinity of the laser light source can be reduced, and the heat generated in the laser drive circuit is effectively released to the optical pickup housing. Insist that you can.

Further, in Patent Document 2, a heat sink is installed in the housing, and the opposite side of the laser driver connecting surface to which the flexible substrate is connected is installed on the heat sink, and the heat sink is installed below the laser driver. A configuration in which a laser driver is installed in a state where a flexible substrate is disposed on the upper side is disclosed.
JP 2002-304758 A (2nd and 3rd pages) JP 2002-252408 A (2nd page)

  However, in the above prior art, both of the objects to transmit heat from the laser light source and the laser driving circuit are both optical pickup housings. Therefore, when both are close to each other, the heat generated in the laser drive circuit is transmitted to the laser light source through the optical pickup housing, which may affect the performance and life of the laser light source.

  Further, in order for the optical pickup device to accurately perform recording and reproduction with respect to a plurality of types of optical discs, it is necessary to adjust and position the laser light source, the photodetector, and the optical components in a plurality of translational and rotational directions. Therefore, each component is not necessarily fixed in contact with the optical pickup casing, but is fixed with an adhesive at a distance of several hundred μm to several mm. In particular, when the laser light source is connected to the optical pickup housing only with a member having a thermal conductivity of less than 1.0 W / m / K, such as a small adhesive, the laser light source becomes hot and the laser light source There was a possibility of affecting the performance and life.

The present invention has been made in view of the situation of the prior art as described above, and an object of the present invention is to provide a highly reliable optical pickup device that prevents performance degradation, life deterioration, and malfunction due to heat generation of a laser light source or a laser driving circuit. And providing an optical disk device .

To achieve the above object, the present invention, the heat radiation path Les chromatography The drive circuit was to be formed directly on the cover or the lower cover without using pickup case. Therefore, the laser drive circuit so as to sandwich a cover and a lower cover on without using pickup case, also, the cover or the lower cover after having connected the record over The driving circuit, the portion where the laser light source is arranged A notch structure larger than the projected area of the laser light source was provided . Furthermore, the connection position between the upper cover or lower cover to which the laser drive circuit is connected and the optical pickup housing is provided in the portion between the laser light source and the laser drive circuit on the edge of the upper cover or lower cover. I tried not to .

Specifically, the first means includes a laser light source that emits a plurality of laser beams for recording and / or reproducing information on a disk that is a recording medium, a laser drive circuit that drives and controls the laser light source, a pickup case for housing the laser light source and the laser drive circuit, the optical pickup apparatus provided with upper and lower covers respectively provided on the upper and lower surfaces of the pickup housing, while said pickup before Symbol upper and lower covers It is attached to a housing via a predetermined gap, and the laser drive circuit is fixed to a cover attached via the gap in a state of ensuring thermal conductivity.

The second means is characterized in that, in the first means, one of the upper and lower covers is a cover disposed on the disk side .

Third means, in the first or second means, so that the cover which the laser driving circuit is mounted through the gap, do not overlap in the vertical projection direction in the cover and the outer shape of the laser light source It is provided.

Fourth means, in the first to third means, the mounting portion with respect to the pickup case of the said cover laser driving circuit is mounted through the gap, the laser driving out end side of the cover It is provided at a position deviated from a portion between the circuit and the plurality of laser light sources.
The fifth means is characterized in that, in any one of the first to fourth means, the laser light source is fixed to the pickup housing in a state in which thermal conductivity is ensured.
The sixth means is characterized in that the optical disk device includes the optical pickup device according to any one of the first to fifth means.

According to the present invention, it is possible to provide the performance degradation due to heat of the laser light source and a laser drive circuit, the deterioration of life, prevent malfunction possible a highly reliable optical pickup device.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 6 is an exploded perspective view of an optical disc apparatus using the optical pickup device according to the embodiment of the present invention. In the figure, an optical disk apparatus 1 includes an apparatus main body 10, a disk tray 4 for carrying a disk as an information recording medium into or out of the apparatus, and electronic components provided in the optical disk apparatus 1. The circuit board 9 on which a semiconductor component that performs drive control and signal processing is mounted is mainly configured. A top cover 2 and a front cover 3 are respectively provided on the upper surface and the front surface of the apparatus main body 10 to cover the upper surface and the front surface of the apparatus main body.

  A unitized mechanism (hereinafter referred to as a unit mechanism) 6 is attached to the disc tray 4, and the bottom surface thereof is covered with a bottom cover 8. The unit mechanism 6 includes a spindle motor 5 for rotating the disk, a recording or reproducing or information reproducing optical pickup 7 for recording or reproducing information on the disk, and an optical pickup 7 as a guide shaft (not shown). An optical pickup feed mechanism configured with a feed motor for moving the disc along the radial direction of the disc is mounted.

  FIG. 7 is a perspective view showing details of the optical pickup 7. In the figure, an optical pickup 7 includes a first laser light source 721 that emits light of a first wavelength and a second laser light source that emits light of a second wavelength in order to record and reproduce information on the disc. 722, a laser drive circuit for driving and controlling the laser light sources 721 and 722, a front monitor for monitoring the outputs of the laser light sources 721 and 722, and optical elements such as prisms, mirrors, and lenses for guiding the laser light to the disk A component, an objective lens driving device 75 having an objective lens for precisely focusing a laser beam at a predetermined position on the information recording surface of the disc, and converting a change in reflected light from the disc into an electric signal And a flexible substrate 76 for inputting / outputting signals by connecting the circuit board 9 and electronic components mounted on the optical pickup 7. And an optical pickup case 71. for mounting them. The upper and lower surfaces of the optical pickup casing 71 are covered with an upper cover 771 and a lower cover 772 for the purpose of holding the flexible substrate 76 and blocking electromagnetic waves from electronic components.

  Among the components mounted on the optical pickup 7, as the components that generate heat during recording or reproduction, a driving coil attached to the objective lens driving device 75, laser light sources 721 and 722, a laser driving circuit, a front monitor, and a photodetector 74. and so on. Among these, the laser light sources 721 and 722 and the laser driving circuit 73 (see FIGS. 1 and 2) are arranged close to each other. In the figure, reference numeral 792 denotes a first fixing member, and 791 denotes a second fixing member.

  FIG. 2 is a perspective view showing the relationship between the laser light source and the first and second fixing members, and FIG. 3 is a diagram when the laser light source is attached to the optical pickup casing 71 using the first and second fixing members. It is sectional drawing which shows a state. Hereinafter, the mounting structure and the heat radiation path of the laser light sources 721 and 722 will be described with reference to FIGS.

  First, the laser light source 72 is press-fitted or brought into surface contact with a metal first fixing member 792 and bonded and fixed. Next, the first fixing member 792 is fixed in surface contact with the metal second fixing member 791. Then, the second fixing member is brought into surface contact with the optical pickup casing 71 and fixed with an adhesive. On the connecting surface of the first fixing member 792 and the second fixing member 791, the first fixing member 792 side is a convex (cylindrical) curved surface having a radius R, and the second fixing member 791 side is a radius R. Even if the laser element 72 is adjusted to rotate around an axis perpendicular to the optical axis (axis B in FIG. 2) by forming a concave curved surface, the first slidable shape is formed. The fixing member 792 and the second fixing member 791 can maintain a surface contact state as shown in FIG. Therefore, the heat generated by the laser light source 72 is efficiently diffused to the first fixing member 792 and the second fixing member 791 and the optical pickup casing 71 and is radiated to the outside of the optical pickup device 7. The temperature of can be kept low.

  FIG. 4 is a cross-sectional view of the laser drive circuit mounting portion of the optical pickup device. The laser drive circuit 73 is connected to the flexible substrate 76 and is disposed in a groove or hole 71 a provided in the vicinity of the fixing portion of the laser light sources 721 and 722 of the optical pickup housing 71. The laser drive circuit 73 is connected to the upper cover 771 closer to the laser drive circuit 73 among the upper and lower covers 771 and 772 by the heat conducting member 78. Thus, the heat generated by the laser drive circuit 73 is transmitted to the upper cover 771 via the heat conducting member 78 and is radiated to the outside of the optical pickup device 7 while being diffused in the in-plane direction of the upper cover 771. Furthermore, by connecting the upper cover 771 with a shorter distance between the upper and lower covers, the thermal resistance between the laser drive circuit 73 and the cover can be kept small, and the temperature of the laser drive circuit 73 can be kept low.

  When the flexible substrate 76 is disposed between the laser drive circuit 73 and the upper cover 771, a through hole 76 a is provided in the flexible substrate 76, and the laser drive circuit 73 and the upper cover 771 connect the flexible substrate 76. It is set as the structure connected only by the heat conductive member 78, without going through. Thereby, compared with the case where the laser drive circuit 73 and the upper cover 771 are connected via the flexible substrate 76, the contact thermal resistance can be reduced, so that the temperature of the laser drive circuit 73 can be kept low. As the heat conductive member 78, a material having a thermal conductivity of 1.0 W / m / K or more such as a resin material containing a metal filler or a silicone resin is used.

  The laser light sources 721 and 722 and the laser drive circuit 73 are connected by a flexible substrate 76, and the flexible substrate 76 exists between the upper cover 771 and the optical pickup housing 71. However, the thickness of the flexible substrate 76 is very thin as 0.10 mm or less, and the heat transfer amount in the flexible substrate 76 is very small. Therefore, the heat generated by the laser drive circuit 73 is radiated to the outside through the heat conducting member 78 and the upper cover 771 or the lower cover 772, and heat is not transmitted to the laser light source 72 through the optical pickup casing 71. The temperature of the laser light sources 721 and 722 can be kept low.

  FIG. 1 is a plan view showing the relationship between the laser casing 71 and the spindle motor. In this embodiment, when the optical pickup device 7 is mounted on the optical disk device, the direction in which the spindle motor 5 is disposed is the inner circumferential direction with respect to the disk that is the recording medium when viewed from the optical pickup device 7. . Conversely, when viewed from the optical pickup device 7, the direction away from the spindle motor 5 is the outer circumferential direction of the disk. In order to perform high-speed control of both of the plurality of laser light sources 721 and 722, it is necessary to dispose the laser drive circuit 73 at a substantially equal distance from the laser light sources 721 and 722 and in the vicinity thereof. In this embodiment, the laser drive circuit 73 is arranged at an approximately equal distance from the two laser light sources 721 and 722 and on the inner peripheral side with respect to the laser light sources 721 and 722. Thereby, compared with the case where the laser drive circuit 73 is arranged on the outer peripheral side of the laser light sources 721 and 722 where the location is hardly secured due to the external dimension restrictions, the area of the upper cover 771 which is a heat dissipation member of the laser drive circuit 73 is reduced. Since it can ensure widely in the position away from the laser light sources 721 and 722, the temperature of the laser drive circuit 73 can be suppressed low.

  When the upper cover 771 to which the laser drive circuit 73 is connected is fixed to the optical pickup housing 71, the projections of the laser light sources 721 and 722 and their fixing members 791 and 792 are arranged so as not to overlap with the outer shapes of the laser light sources 721 and 722. Not less than the area. In other words, an upper cover 771 is not provided on the upper surfaces of the laser light sources 721 and 722 and their fixing members 791 and 792. This notched portion is denoted by reference numeral C in FIGS. Accordingly, since the heat radiation of the laser light sources 721 and 722 is not hindered by the upper cover 771 that has become high temperature due to the heat generated by the laser drive circuit 73, the temperature of the laser light sources 721 and 722 can be kept low.

  However, it is necessary to press the flexible substrate 76 with the covers 771 and 772 so that the flexible substrate 76 does not float and hit the disk. Therefore, in this embodiment, the flexible substrate 76 between the laser drive circuit 73 and the laser light sources 721 and 722 is not disposed in the cutout portion C of the upper cover 771 above the laser light sources 721 and 722 as shown in FIG. It is arranged on the lower surface of the optical pickup casing 71. That is, as shown in FIG. 7, the connection end of the flexible substrate 76 with the second laser light source 722 is bent upward from the lower surface of the pickup housing 71 and extends to the connection terminal portion of the second laser light source, Connected. In this way, the flexible substrate 76 between the laser drive circuit 73 and the laser light sources 721 and 722 is pressed by the optical pickup casing 71 and the lower cover 772, so that the flexible substrate 76 does not float.

  Further, the upper cover 771 to which the laser driving circuit 73 is connected is partially connected to and attached to the optical pickup housing 7 as shown in FIG. That is, in the present embodiment, the position of the connection portion A between the upper cover 771 to which the laser drive circuit 73 is connected and the optical pickup housing 7 is set so that the laser light sources 721 and 722 and the laser drive circuit are located on the end side of the upper cover 771. It was not provided in the part D between 73. The portion D includes a line D1 connecting an end portion farthest from the second laser light source 722 of the first laser light source 721 and an end portion on the same side of the laser driving circuit 73 in FIG. 722 is a portion between an end portion farthest from the first laser light source 721 and an end portion on the same side of the laser driving circuit 73, and the connection portion A is connected to the line D2 as shown in FIG. It is located outside D1 and D2. As a result, the heat generated by the laser drive circuit 73 is transmitted from the upper cover 771 to the vicinity of the laser light sources 721 and 722 of the optical pickup casing 71 and does not obstruct the heat radiation of the laser light sources 721 and 722. , 722 can be kept low.

In this embodiment, as shown in FIG. 4, a hole 76a is formed in the flexible substrate 76, and the laser drive circuit 73 and the upper cover 771 are thermally connected so that the heat conducting member 78 is positioned in the hole 76a. However, in addition to this, it is also possible to configure as shown in FIG. In another embodiment, when the flexible substrate 76 is interposed between the laser drive circuit 73 and the upper cover 771, both opposing surfaces of the flexible substrate 76 and the laser drive circuit 73 are used as conductor surfaces. The conductor surface of the laser drive circuit 73 and the conductor surface of the flexible substrate 76 are connected by the first heat conducting member 781, and the flexible substrate 76 and the upper cover 771 are connected by the second heat conducting member 782. The first heat conductive member 781 is a conductive material such as a resin material containing metal filler or solder. The second heat conducting member has a thermal conductivity of 1.0 W / m / K or more, such as a resin material containing a metal filler or a silicone resin. As a result, the first heat conducting member 781 is moved to the laser driving circuit 7 while keeping the thermal resistance from the laser driving circuit 73 to the upper cover 771 small.
Runode even you to use as a third ground wiring, it is possible to improve the electrical characteristics of the laser drive circuit 73.

  Moreover, it can also comprise as shown in FIG. In yet another embodiment, the lower cover 772 that is not connected to the laser drive circuit 73 in FIG. 4 is also connected to the laser drive circuit 73 via the third heat conducting member 783. The third heat conducting member 783 is a resin material containing a metal filler, a silicone resin, or the like. Thereby, since the heat radiation path from the laser drive circuit 73 can be increased, the temperature of the laser drive circuit 73 can be further reduced.

  As described above, according to the present embodiment, the laser light source is connected to the optical pickup housing with the metal member, and the laser driving circuit is connected to the upper cover or the lower cover without going through the optical pickup housing. And the laser drive circuit do not interfere with each other's heat dissipation. Accordingly, the temperature of both the laser light source and the laser drive circuit can be kept low, and the performance deterioration, life deterioration, and malfunction of the heat-generating component can be prevented, so that the reliability can be improved and a high-quality optical pickup device is provided. be able to.

It is a top view of the optical pick-up apparatus which shows the arrangement | positioning relationship between the laser drive circuit and laser light source which concern on one Example of this invention. It is a disassembled perspective view of the laser light source which concerns on one Example of this invention, and its fixing member. It is sectional drawing of the laser light source attachment part of the optical pick-up apparatus which concerns on one Example of this invention. It is sectional drawing of the laser drive circuit attachment part of the optical pick-up apparatus which concerns on one Example of this invention. It is a top view of the optical pick-up apparatus which shows the positional relationship of the upper cover fixing | fixed part which concerns on one Example of this invention, a laser drive circuit, and a laser light source. 1 is an exploded perspective view of an optical disc device to which an optical pickup device of the present invention is applied. 1 is a perspective view of an optical pickup device according to an embodiment of the present invention. It is sectional drawing of the laser drive circuit attachment part of the optical pick-up apparatus which concerns on the other Example of this invention. It is sectional drawing of the laser drive circuit attachment part of the optical pick-up apparatus based on the further another Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 5 Spindle motor 7 Optical pick-up 71 Optical pick-up housing 72 Laser light source 721 1st laser light source 722 2nd laser light source 73 Laser drive circuit 74 Photo detector 75 Objective lens drive device 76 Flexible board 771 Upper cover 772 Lower Cover 78 Heat conduction member 781 First heat conduction member 782 Second heat conduction member 783 Third heat conduction member 791 Second fixing member 792 First fixing member 10 Device body A Connection portion D First and second Between the laser light source and the laser drive circuit

Claims (6)

A laser light source that emits a plurality of laser beams for recording and / or reproducing information on a disk that is a recording medium ;
A laser driving circuit for driving and controlling the laser light source;
A pickup housing for housing the laser light source and the laser driving circuit;
In the optical pickup device comprising upper and lower covers respectively provided on the upper surface and the lower surface of the pickup housing ,
One of the upper and lower covers is attached to the pickup housing via a predetermined gap,
An optical pickup device, wherein the laser driving circuit is fixed to a cover attached via the gap in a state of ensuring thermal conductivity . 2. The optical pickup device according to claim 1 , wherein one of the upper and lower covers is a cover disposed on the disk side . The cover the laser driving circuit is mounted through the gap, according to claim 1 or 2, characterized in that provided so as not to overlap in a vertical projection direction in the cover and the outer shape of the laser light source Optical pickup device. An attachment portion of the cover, to which the laser drive circuit is attached via the gap, with respect to the pickup housing is separated from a portion between the laser drive circuit and the plurality of laser light sources on the edge of the cover. the optical pickup device according to any one of claims 1 to 3, characterized in that provided in the position. The optical pickup device according to any one of claims 1 to 4, characterized in that the laser light source is fixed while securing thermal conductivity to the pickup case. An optical disc apparatus comprising the optical pickup device according to claim 1 .

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